Just how bad is inhaling smoke?

It's been well established that inhaling smoke is bad for you compared to not inhaling smoke; I'm curious how various types of smoke inhalation compare. For example, 5 minutes of breathing smoke from an indoor wood fireplace with faulty ventilation versus the same time breathing from an enclosed space where someone has been smoking, versus 5 minutes of exposure to smoke from a house fire? At the same density of smoke, is one considerably worse than the other, considering both short term and long term effects?

Well, biology definitely isn't my thing, so I have only limited ability to interpret what I'm reading, but the top few results, mostly about general air pollution, paint a picture somewhat at odds with the conventional wisdom. Acute symptoms are rather nasty, but having been removed from exposure for some months, people recovered significantly. Various papers and govt websites talk of particles 2.5 microns in diameter being the main cause of damage, at least in the short term and in the context of air quality(including exposure to wildfires and the like). I see another paper that questions any causal link between inhaling small diameter airborne particles and long term mortality increase however, and that it would take between a two and tree order of magnitude increase in normal (everyday air pollution) exposure to have significant effects.

This is somewhat at odds with the conventional "Exposure to smoke is going to kill you, if not immediately, then slowly and unpleasantly." Sort of makes more questions than it answers.

While serving aboard ship we had fire drills every day - and everybody was trained with respirators, fire hoses, etc.

One training exercise was in a water tight compartment below deck - which was filled with smoke from a controlled device - we spent five minutes with a respirator, and then were to take it off, take a breath, and exit.

One breath of heavy smoke and your eyes were in tears, and you started coughing. Some had to be helped to exit the compartment.

I don't know how they do it today - my experience was in 1968 - but I would never expose myself to smoke on purpose!

In selecting your articles you should look for a recent "review article" which summarizes much of the previous work. Individual studies are hard to understand for the non-specialist, and depending upon the experimental setup, controls, and statistics ... may be unreliable, or misleading.

A review article will be written by an expert in the field with many years of experience, and will review the state of the field, and go over many individual articles and studies ... and draw some conclusions. You can then follow up by reading some of the individual papers that are referenced.